Intermediate film for laminated glass, and laminated glass

ABSTRACT

An object of the present invention is to provide an interlayer film for laminated glass which produces a high contrast image under light radiation, is less susceptible to color changes, and allows for control of the adhesion. Another object of the present invention is to provide a laminated glass including the interlayer film for laminated glass. 
     The present invention provides an interlayer film for laminated glass which includes a light emitting layer containing a polyvinyl acetal, a light emitting material having a terephthalic acid ester structure, and a potassium salt.

TECHNICAL FIELD

The present invention relates to an interlayer film for laminated glasswhich produces a high contrast image under light radiation, is lesssusceptible to color changes, and allows for control of the adhesion.The present invention further relates to a laminated glass including theinterlayer film for laminated glass.

BACKGROUND ART

Laminated glass has a variety of uses, such as in front, side and rearwindshields of vehicles (e.g. automobiles) and windowpanes of aircraft,buildings, and the like, because it is a form of safety glass that isless likely to scatter even when shattered by external impact. A knownexample of laminated glass is a laminated glass including at least apair of glass plates integrated through, for example, an interlayer filmfor laminated glass which contains a liquid plasticizer and a polyvinylacetal resin.

A recent growing need is the development of a head-up display (HUD) thatpresents meters showing vehicle driving data (e.g. driving speedinformation) within a usual range of vision in the front windshield of avehicle.

There have been known various types of HUDs. The most typical one is aHUD that is designed such that a display unit of an instrumental panelprojects information (e.g. driving speed information) sent from acontrol unit onto a front windshield to enable a driver to view theinformation at a usual viewpoint, that is, within a usual range ofvision in the front windshield.

An example of laminated glass interlayer films for a HUD is awedge-shaped laminated glass interlayer film with a predetermined wedgeshape proposed in Patent Literature 1. This interlayer film can solve aHUDs' problem that a meter image displayed on a laminated glass appearsdouble.

Patent Literature 1 also discloses a laminated glass that is partiallyfree from the HUDs' problem that a meter image appears double. Yet, notthe entire surface of the laminated glass is free from the double meterimage problem.

Patent Literature 2 discloses a laminated glass including a laminate ofan interlayer containing hydroxy terephthalate between two transparentplates. Patent Literature 2 also discloses a laminated glass thatproduces a high contrast image under light radiation. Unfortunately, inthe case of such a laminated glass including an interlayer containinghydroxy terephthalate, the interlayer is susceptible to color changes.

CITATION LIST Patent Literature

Patent Literature 1: JP H4-502525 T

Patent Literature 2: WO 2010/139889

SUMMARY OF INVENTION Technical Problem

An object of the present invention is to provide an interlayer film forlaminated glass which produces a high contrast image under lightradiation, is less susceptible to color changes, and allows for controlof the adhesion. Another object of the present invention is to provide alaminated glass including the interlayer film for laminated glass.

Solution to Problem

The present invention provides an interlayer film for laminated glasswhich includes a light emitting layer containing a polyvinyl acetal, alight emitting material having a terephthalic acid ester structure, anda potassium salt.

The following description is offered to demonstrate the presentinvention.

The present inventors have found that an interlayer film for laminatedglass which includes a light emitting layer containing a polyvinylacetal, a light emitting material having a terephthalic acid esterstructure, and a potassium salt produces a high contrast image underlight radiation, is less susceptible to color changes, and allows forcontrol of the adhesion. This has led to the completion of the presentinvention.

The interlayer film for laminated glass of the present inventionincludes a light emitting layer containing a polyvinyl acetal, a lightemitting material having a terephthalic acid ester structure, and apotassium salt. Typically, interlayer films for laminated glass containa magnesium element-containing compound as an adhesion control agent forcontrolling the adhesion of the interlayer films for laminated glass toglass. The present inventors found a problem that the use of a lightemitting material having a terephthalic acid ester structure incombination with a magnesium magnesium element-containing compoundresults in an interlayer film for laminated glass which undergoes acolor change. However, the presence of a light emitting layer containinga polyvinyl acetal, a light emitting material having a terephthalic acidester structure, and a potassium salt allows for display of a highcontrast image, prevents color changes, and allows for control of theadhesion of the interlayer film for laminated glass.

The interlayer film for laminated glass of the present invention may bea single-layered interlayer film consisting of the light emitting layer,or may be a multilayered interlayer film including the light emittinglayer and a first resin layer disposed on or above one surface of thelight emitting layer. The first resin layer preferably contains apolyvinyl acetal. The first resin layer may be directly disposed on onesurface of the light emitting layer.

In the case where the interlayer film for laminated glass of the presentinvention is a multilayered interlayer film, it is preferable that thelight emitting layer constitutes the outermost layers of themultilayered interlayer film. This structure allows for control of theadhesion to glass.

The light emitting layer contains a polyvinyl acetal.

The polyvinyl acetal is not particularly limited, as long as it isobtained by acetalization of polyvinyl alcohol with an aldehyde.Preferred is polyvinyl butyral. Two or more polyvinyl acetals may beused as needed.

As for the degree of acetalization of the polyvinyl acetal, thepreferable lower limit is 40 mol %, the preferable upper limit is 85 mol%, the more preferable lower limit is 60 mol %, and the more preferableupper limit is 75 mol %.

As for the hydroxyl group content of the polyvinyl acetal, thepreferable lower limit is 15 mol %, and the preferable upper limit is 35mol %. When the hydroxyl group content is 15 mol % or more, theinterlayer film for laminated glass can be easily formed; when thehydroxyl group content is 35 mol % or less, the interlayer film forlaminated glass is easy to handle.

The degree of acetalization and the hydroxyl group content can bemeasured in accordance with, for example, JIS K 6728, “Testing methodfor polyvinyl butyral”.

The polyvinyl acetal can be prepared by acetalization of polyvinylalcohol with an aldehyde. The polyvinyl alcohol is typically prepared bysaponification of polyvinyl acetate, and a polyvinyl alcohol having adegree of saponification of 70 to 99.8 mol % is generally used.

As for the degree of polymerization of the polyvinyl alcohol, thepreferable lower limit is 500, and the preferable upper limit is 4000. Apolyvinyl alcohol with a degree of polymerization of 500 or moreprovides penetration resistance to a laminated glass to be formed.

In the case of a polyvinyl alcohol with a degree of polymerization of4000 or less, the interlayer film for laminated glass can be easilyformed. The more preferable lower limit of the degree of polymerizationof the polyvinyl alcohol is 1000, and the more preferable upper limit is3600.

The aldehyde is not particularly limited, and typically, a C1 to C10aldehyde is suitable. The C1 to C10 aldehyde is not particularlylimited, and examples include n-butyl aldehyde, isobutyl aldehyde,n-valeraldehyde, 2-ethyl butyl aldehyde, n-hexyl aldehyde, n-octylaldehyde, n-nonyl aldehyde, n-decyl aldehyde, formaldehyde,acetaldehyde, and benzaldehyde. Preferred among these are n-butylaldehyde, n-hexyl aldehyde, and n-valeraldehyde, and more preferred isn-butyl aldehyde. Any of these aldehydes may be used alone, or two ormore of them may be used in combination.

The light emitting layer contains a light emitting material having aterephthalic acid ester structure.

The light emitting material having a terephthalic acid ester structureemits light under light radiation. The light radiation is notparticularly limited, as long as it excites the light emitting materialhaving a terephthalic acid ester structure to cause it to emit light.Examples include ultraviolet radiation and infrared radiation.

Examples of the light emitting material having a terephthalic acid esterstructure include a compound having a structure represented by thefollowing formula (1) and a compound having a structure represented bythe following formula (2). Any of these may be used alone, or two ormore of these may be used in combination.

In the formula (1), R¹ is an organic group, and x is 1, 2, 3 or 4. Inorder to ensure that the interlayer film for laminated glass has muchhigher transparency, it is preferable that x is 1 or 2, more preferablethat the benzene ring has a hydroxyl group at a 2- or 5-position, andstill more preferable that the benzene ring has hydroxyl groups at the2- and 5-positions.

The organic group of R¹ is preferably a hydrocarbon group, morepreferably a C1 to C10 hydrocarbon group, still more preferably a C1 toC5 hydrocarbon group, and particularly preferably a C1 to C3 hydrocarbongroup. In the case of a hydrocarbon group with 10 or less carbon atoms,the light emitting material having a terephthalic acid ester structurecan be easily dispersed in the interlayer film for laminated glass. Thehydrocarbon is preferably an alkyl group.

Examples of the compound having a structure represented by the formula(1) include diethyl-2,5-dihydroxy terephthalate anddimethyl-2,5-dihydroxy terephthalate. In particular, the compound havinga structure represented by the formula (1) is preferablydiethyl-2,5-dihydroxy terephthalate(“diethyl-2,5-dihydroxyterephthalate” from Aldrich) because it allowsfor display of an image with a much higher contrast.

In the formula (2), R² is an organic group, R³ and R⁴ are individually ahydrogen atom or an organic group, and y is 1, 2, 3 or 4.

The organic group of R² is preferably a hydrocarbon group, morepreferably a C1 to C10 hydrocarbon group, still more preferably a C1 to05 hydrocarbon group, and particularly preferably a C1 to C3 hydrocarbongroup. When the carbon number of the hydrocarbon group is the upperlimit or less, the light emitting material having a terephthalic acidester structure can be easily dispersed in the interlayer film forlaminated glass. The hydrocarbon is preferably an alkyl group.

In the formula (2), NR³R⁴ is an amino group. Preferably, R³ and R⁴ areindividually a hydrogen atom. The amino group may be substituted for oneof the hydrogen atoms of the benzene ring of the compound having astructure represented by the formula (2), or may be substituted for two,three, or four of the hydrogen atoms.

The compound having a structure represented by the formula (2) ispreferably diethyl-2,5-diamino terephthalate (from Aldrich) because itallows for display of an image with a much higher contrast.

The amount of the light emitting material having a terephthalic acidester structure is not particularly limited, but the preferable lowerlimit is 0.001 parts by weight for 100 parts by weight of the polyvinylacetal, and the preferable upper limit is 5 parts by weight. When theamount of the light emitting material having a terephthalic acid esterstructure is 0.001 parts by weight or more, the interlayer film forlaminated glass can produce an image with a much higher contrast underlight radiation; when the amount of the light emitting material having aterephthalic acid ester structure is 5 parts by weight or less, theinterlayer film for laminated glass has much higher transparency. Themore preferable lower limit of the amount of the light emitting materialhaving a terephthalic acid ester structure is 0.005 parts by weight, themore preferable upper limit is 2 parts by weight, the still morepreferable lower limit is 0.01 parts by weight, the still morepreferable upper limit is 1.5 parts by weight, the particularlypreferable lower limit is 0.1 parts by weight, and the particularlypreferable upper limit is 1 part by weight.

The light emitting layer contains the potassium salt. The presence ofthe potassium salt not only facilitates control of the adhesion of thelight emitting layer to glass, but also prevents color changes of thelight emitting layer. The potassium salt is not particularly limited,but is preferably a C1 to C16 organic acid potassium salt, morepreferably a C2 to C16 organic acid potassium salt, still morepreferably a C1 to C16 carboxylic acid potassium salt, and particularlypreferably a C2 to C16 carboxylic acid potassium salt. The C1 to C16carboxylic acid potassium salt is not particularly limited, and examplesinclude potassium formate, potassium acetate, potassium propionate,potassium 2-ethylbutanoate, and potassium 2-ethylhexanoate. Or, the C1to C16 carboxylic acid potassium salt may be potassium acetate,potassium propionate, potassium 2-ethylbutanoate, or potassium2-ethylhexanoate. The C1 to C16 carboxylic acid is preferably acarboxylic acid with 12 or less carbon atoms, more preferably acarboxylic acid with 10 or less carbon atoms, and still more preferablya carboxylic acid with 8 or less carbon atoms.

The term “color change” means that when the interlayer film forlaminated glass is inserted between two clear glass plates (thickness:2.5 mm), the resulting laminated glass has a YI value of more than 20.The YI value can be determined with a spectrophotometer (U-4100 fromHitachi High-Technologies Corporation) in accordance with JIS Z 8722.The YI value is preferably 20 or less, more preferably 15 or less, andstill more preferably 10 or less. Also preferably, the YI value is 0 ormore.

The amount of the potassium salt is not particularly limited, but thepreferable lower limit is 0.001 parts by weight for 100 parts by weightof the polyvinyl acetal, and the preferable upper limit is 0.5 parts byweight. When the amount of the potassium salt is 0.001 parts by weightor more, a laminated glass with high penetration resistance can beobtained; when the amount of the potassium salt is 0.5 parts by weightor less, the interlayer film for laminated glass has highertransparency. The more preferable lower limit of the amount of thepotassium salt is 0.015 parts by weight, the more preferable upper limitis 0.25 parts by weight, the still more preferable lower limit is 0.02parts by weight, the still more preferable upper limit is 0.2 parts byweight, the particularly preferable lower limit is 0.025 parts byweight, and the particularly preferable upper limit is 0.1 parts byweight.

In order to more effectively prevent color changes of the light emittinglayer, the potassium element content of the light emitting layer ispreferably 400 ppm or less, more preferably 300 ppm or less, still morepreferably 250 ppm or less, particularly preferably 200 ppm or less, andmost preferably 180 ppm or less. In order to ensure that the lightemitting layer has high moisture resistance, the potassium elementcontent of the light emitting layer is most preferably 100 ppm or less.The potassium element may be potassium derived from the potassium salt,or may be potassium derived from a neutralizer used for the synthesis ofthe polyvinyl acetal. The preferable lower limit of the potassiumelement content of the light emitting layer is 30 ppm, the morepreferable lower limit is 40 ppm, the still more preferable lower limitis 80 ppm, and the particularly preferable lower limit is 120 ppm.

The light emitting layer may contain a magnesium salt, as long as itdoes not prevent the objects of the present invention. The presence of amagnesium salt further facilitates control of the adhesion of the lightemitting layer to glass. The magnesium salt is not particularly limited,and is preferably a C2 to C16 organic acid magnesium salt, and morepreferably a C2 to C16 carboxylic acid magnesium salt. The C2 to C16carboxylic acid magnesium salt is not particularly limited, and examplesinclude magnesium acetate, magnesium propionate, magnesium2-ethylbutanoate, and magnesium 2-ethylhexanoate. The C2 to C16carboxylic acid magnesium salt is preferably magnesium acetate becauseit further facilitates control of the adhesion of the light emittinglayer to glass.

The amount of the magnesium salt is not particularly limited, but thepreferable lower limit is 0.02 parts by weight for 100 parts by weightof the polyvinyl acetal, and the preferable upper limit is 0.5 parts byweight. When the amount of the magnesium salt is 0.02 parts by weight ormore, a laminated glass with high penetration resistance can beobtained; when the amount of the magnesium salt is 0.5 parts by weightor less, the interlayer film for laminated glass has high transparency.The more preferable lower limit of the amount of the magnesium salt is0.03 parts by weight, the more preferable upper limit is 0.2 parts byweight, the still more preferable lower limit is 0.04 parts by weight,and the still more preferable upper limit is 0.1 parts by weight.

In order to further facilitate control of the adhesion of the interlayerfilm for laminated glass of the present invention, and to moreeffectively prevent color changes, the magnesium element content of thelight emitting layer is preferably 80 ppm or less. The magnesium elementmay be magnesium derived from the magnesium salt, or may be magnesiumderived from a neutralizer used for the synthesis of the polyvinylacetal. The preferable lower limit of the magnesium element content ofthe light emitting layer is 0 ppm, the more preferable upper limit is 75ppm, the more preferable lower limit is 20 ppm, the still morepreferable upper limit is 70 ppm, and the still more preferable lowerlimit is 30 ppm. The potassium element content and the magnesium elementcontent can be determined with an ICP emission spectrometer (“ICPE-9000”from Shimadzu Corp.).

In order to more effectively prevent color changes of the interlayerfilm for laminated glass, the light emitting layer preferably containslithium element at a concentration of 25 ppm or less. The morepreferable lower limit of the lithium element concentration of the lightemitting layer is 0 ppm, the more preferable upper limit is 20 ppm, thestill more preferable lower limit is 1 ppm, and the still morepreferable upper limit is 10 ppm.

The light emitting layer preferably further contains a dispersant. Thepresence of a dispersant prevents the light emitting material having aterephthalic acid ester structure from aggregating, and allows for moreuniform light emission. Examples of the dispersant include compoundshaving a sulfonic acid structure such as salts of a linearalkylbenzenesulfonic acid, compounds having an ester structure such asdiester compounds, alkyl esters of recinoleic acid, phthalic acidesters, adipic acid esters, sebacic acid esters, and phosphoric acidesters, compounds having an ether structure such as polyoxyethyleneglycol, polyoxypropylene glycol, and alkylphenyl-polyoxyethylene-ethers,compounds having a carboxylic acid structure such as polycarboxylicacids, compounds having an amine structure such as laurylamine,dimethyllaurylamine, oleyl propylene diamine, polyoxyethylene secondaryamines, polyoxyethylene tertiary amines, and polyoxyethylene diamines,compounds having a polyamine structure such as polyalkylene polyaminealkylene oxides, compounds having an amide structure such as oleic aciddiethanolamide and fatty acid alkanolamides, and compounds having a highmolecular weight amide structure such as polyvinyl pyrrolidone andpolyester acid amide amine salts. Other examples include high molecularweight dispersants such as polyoxyethylene alkyl ether phosphates(salts), polycarboxylic acid polymers, and condensed ricinoleic acidesters. The term “high molecular weight dispersant” is defined asreferring to dispersants having a molecular weight of 10000 or higher.

In the case where the dispersant is used, the preferable lower limit ofthe amount of the dispersant in the light emitting layer is 1 part byweight for 100 parts by weight of the light emitting material having aterephthalic acid ester structure in the light emitting layer, and thepreferable upper limit is 50 parts by weight. When the amount of thedispersant is within the range, the light emitting material having aterephthalic acid ester structure can be homogeneously dispersed in thelight emitting layer. The more preferable lower limit of the amount ofthe dispersant is 3 parts by weight, the more preferable upper limit is30 parts by weight, the still more preferable lower limit is 5 parts byweight, and the still more preferable upper limit is 25 parts by weight.

The light emitting layer preferably further contains an ultravioletabsorber. The presence of an ultraviolet absorber in the light emittinglayer improves the lightfastness of the light emitting layer. The lightemitting layer may not contain any ultraviolet absorber. In order toensure that the interlayer film for laminated glass can produce an imagewith a much higher contrast, the preferable upper limit of the amount ofthe ultraviolet absorber in the light emitting layer is 1 part by weightfor 100 parts by weight of the polyvinyl acetal, the more preferableupper limit is 0.5 parts by weight, the still more preferable upperlimit is 0.2 parts by weight, and the particularly preferable upperlimit is 0.1 parts by weight.

Examples of the ultraviolet absorber include compounds having an malonicacid ester structure, compounds having an oxalic anilide structure,compounds having a benzotriazole structure, compounds having abenzophenone structure, compounds having a triazine structure, compoundshaving a benzoate structure, and compounds having a hindered aminestructure.

The light emitting layer may further contain a plasticizer as needed.The plasticizer is not particularly limited, and examples includeorganic ester plasticizers such as monoprotic organic acid esters andpolyprotic organic acid esters, and phosphoric acid plasticizers such asorganic phosphoric acid plasticizers and organic phosphorous acidplasticizers. The plasticizer is preferably a liquid plasticizer.

The monoprotic organic acid esters are not particularly limited, andexamples include glycolesters obtainable by the reaction of a glycol(e.g. triethylene glycol, tetraethylene glycol, or tripropyleneglycol)and a monoprotic organic acid (e.g. butyric acid, isobutyric acid,caproic acid, 2-ethylbutyric acid, heptanoic acid, n-octylic acid,2-ethylhexyl acid, pelargonic acid (n-nonylic acid), or decylic acid).In particular, triethylene glycol dicaproate, triethylene glycoldi-2-ethylbutyrate, triethylene glycol di-n-octylate, and triethyleneglycol di-2-ethylhexylate are preferable.

The polyprotic organic acid esters are not particularly limited, andexamples include ester compounds of a polyprotic organic acid (e.g.adipic acid, sebacic acid, or azelaic acid) and a C4 to C8 linear orbranched alcohol. In particular, dibutyl sebacate, dioctyl azelate,dibutylcarbitol adipate, and the like are preferable.

The organic ester plasticizers are not particularly limited, andexamples include triethylene glycol di-2-ethyl butyrate, triethyleneglycol di-2-ethylhexanoate, triethylene glycol dicaprylate, triethyleneglycol di-n-octanoate, triethylene glycol di-n-heptanoate, tetraethyleneglycol di-n-heptanoate, tetraethylene glycol di-2-ethylhexanoate,dibutyl sebacate, dioctyl azelate, dibutyl carbitol adipate, ethyleneglycol di-2-ethyl butyrate, 1,3-propylene glycol di-2-ethylbutyrate,1,4-butylene glycol di-2-ethylbutyrate, diethylene glycoldi-2-ethylbutyrate, diethylene glycol di-2-ethylhexanoate, dipropyleneglycol di-2-ethylbutyrate, triethylene glycol di-2-ethylpentanoate,tetraethylene glycol di-2-ethylbutyrate, diethylene glycol dicapriate,dihexyl adipate, dioctyl adipate, hexylcyclohexyl adipate, diisononyladipate, heptyl nonyl adipate, dibutyl sebacate, oil-modified alkydsebacate, mixtures of a phosphoric acid ester and an adipic acid ester,mixed adipic acid esters produced from an adipic acid ester, a C4 to C9alkyl alcohol, and a C4 to C9 cyclic alcohol, and C6 to C8 adipic acidesters such as hexyl adipate.

The organic phosphoric acid plasticizers are not particularly limited,and examples include tributoxyethyl phosphate, isodecylphenyl phosphate,and triisopropyl phosphate.

Preferred among the plasticizers is at least one selected from the groupconsisting of dihexyladipate (DHA), triethylene glycoldi-2-ethylhexanoate (3GO), tetraethylene glycol di-2-ethylhexanoate(4GO), triethylene glycol di-2-ethylbutylate (3GH), tetraethylene glycoldi-2-ethylbutylate (4GH), tetraethylene glycol di-n-heptanoate (4G7),and triethylene glycol di-n-heptanoate (3G7).

Furthermore, the plasticizer preferably includes triethylene glycoldi-2-ethylhexanoate (3GO), triethylene glycol di-2-ethylbutylate (3GH),tetraethylene glycol di-2-ethylhexanoate (4GO), and/or dihexyladipate(DHA), more preferably includes tetraethylene glycol di-2-ethylhexanoate(4GO) and/or triethylene glycol di-2-ethylhexanoate (3GO), and stillmore preferably includes triethylene glycol di-2-ethylhexanoate becausethey are less likely to undergo hydrolysis.

The amount of the plasticizer in the light emitting layer is notparticularly limited, but the preferable lower limit is 20 parts byweight for 100 parts by weight of the polyvinyl acetal, and thepreferable upper limit is 80 parts by weight. When the amount of theplasticizer is 20 parts by weight or more, the interlayer film forlaminated glass has low melt viscosity, which facilitates formation ofthe interlayer film for laminated glass; when the amount of theplasticizer is 80 parts by weight or less, the interlayer film forlaminated glass has high transparency. The more preferable lower limitof the amount of the plasticizer is 30 parts by weight, the morepreferable upper limit is 70 parts by weight, the still more preferablelower limit is 35 parts by weight, and the still more preferable upperlimit is 63 parts by weight.

The light emitting layer may contain additives such as an antioxidant, aphotostabilizer, an antistatic agent, a blue dye, a blue pigment, agreen dye, and/or a green pigment as needed.

The light emitting layer preferably contains an antioxidant because itprovides high lightfastness. The antioxidant is not particularlylimited, and examples include antioxidants having a phenolic structure,sulfur-containing antioxidants, and phosphorus-containing antioxidants.

The antioxidants having a phenolic structure are intended to includeantioxidants having a phenolic backbone. Examples of the antioxidantshaving a phenolic structure include 2,6-di-t-butyl-p-cresol (BHT),butylated hydroxyanisole (BHA), 2,6-di-t-butyl-4-ethylphenol,stearyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate,2,2′-methylenebis-(4-methyl-6-butylphenol),2,2′-methylenebis-(4-ethyl-6-t-butylphenol),4,4′-butylidene-bis-(3-methyl-6-t-butylphenol),1,1,3-tris-(2-methyl-hydroxy-5-t-butylphenyl)butane,tetrakis[methylene-3-(3′,5′-butyl-4-hydroxyphenyl)propionate]methane,1,3,3-tris-(2-methyl-4-hydroxy-5-t-butylphenol)butane,1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene,bis(3,3′-t-butylphenol)butyric acid glycol ester, andpentaerythritoltetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].Any of the antioxidants may be used alone, or two or more of these maybe used in combination.

The thickness of the light emitting layer is not particularly limited,but the preferable lower limit is 300 μm, and the preferable upper limitis 2000 μm. When the thickness of the light emitting layer is withinthis range, the light emitting layer emits light with sufficiently highcontrast under radiation of light at specific wavelengths. The morepreferable lower limit of the thickness of the light emitting layer is350 μm, and the more preferable upper limit is 1000 μm.

The light emitting layer may extend over all the surfaces of theinterlayer film for laminated glass of the present invention, or over apart of the surfaces, or may extend over an entire surface that isperpendicular to the thickness direction of the interlayer film forlaminated glass of the present invention, or over a part of the surface.In the case where the light emitting layer extends over a part of asurface, the covered part functions as a light emitting area, and theother part functions as a non-light emitting area, so that informationcan be displayed only in the light emitting area.

The interlayer film for laminated glass of the present invention mayfurther be provided with a first resin layer on or above one surface ofthe light emitting layer. The first resin layer preferably contains apolyvinyl acetal, more preferably contains a polyvinyl acetal and aplasticizer, and still more preferably contains a polyvinyl acetal, aplasticizer, and an adhesion control agent. Other layer(s) may furtherbe laminated on the light emitting layer and the first resin layer.Examples of the other layer(s) include a layer made of a thermoplasticresin such as polyethylene terephthalate or a polyvinyl acetal. Theother layer(s) may be an ultraviolet shielding coat layer containing anultraviolet absorber. The ultraviolet absorber used in the ultravioletshielding coat layer may be the same ultraviolet absorber as that usedin the light emitting layer.

The polyvinyl acetal in the light emitting layer may be used as thepolyvinyl acetal in the first resin layer. The polyvinyl acetal in thefirst resin layer may be the same as or different from the polyvinylacetal in the light emitting layer. In the case where the light emittinglayer contains a plasticizer, the first resin layer may contain the sameplasticizer as or a different plasticizer from that in the lightemitting layer.

The first resin layer preferably contains an adhesion control agent. Theadhesion control agent is not particularly limited. Preferred are metalsalts, and at least one metal salt selected from the group consisting ofalkali metal salts, alkaline earth metal salts, and magnesium salts ismore preferable. The metal salt preferably contains at least one ofpotassium and magnesium. The metal salt is more preferably an alkalimetal salt of a C2 to C16 organic acid or an alkaline earth metal saltof a C2 to C16 organic acid, and still more preferably a C2 to C16carboxylic acid magnesium salt or a C2 to C16 carboxylic acid potassiumsalt. The C2 to C16 carboxylic acid magnesium salt and the C2 to C16carboxylic acid potassium salt are not particularly limited. Preferredexamples include magnesium acetate, potassium acetate, magnesiumpropionate, potassium propionate, magnesium 2-ethylbutanoate, potassium2-ethylbutanoate, magnesium 2-ethylhexanonate, and potassium2-ethylhexanoate.

The amount of the adhesion control agent is not particularly limited,and the preferable lower limit is 0.0005 parts by weight for 100 partsby weight of the polyvinyl acetal, and the preferable upper limit is0.05 parts by weight. When the amount of the adhesion control agent is0.0005 parts by weight or more, a laminated glass having higherpenetration resistance can be obtained; when the amount of the adhesioncontrol agent is 0.05 parts by weight or less, the interlayer film forlaminated glass has high transparency. The more preferable lower limitof the amount of the adhesion control agent is 0.002 parts by weight,and the more preferable upper limit is 0.02 parts by weight.

The total amount of alkali metals, alkaline earth metals, and magnesiumin the first resin layer is preferably 300 ppm or less in order toensure that the first resin layer has high moisture resistance. Forexample, the alkali metals, alkaline earth metals, and magnesium may bemetals derived from the adhesion control agent, or may be metals derivedfrom a neutralizer used for the synthesis of the polyvinyl acetal. Thetotal amount of alkali metals, alkaline earth metals, and magnesium inthe first resin layer is more preferably 200 ppm or less, still morepreferably 150 ppm or less, and particularly preferably 100 ppm or less.

In the case where the interlayer film for laminated glass of the presentinvention is required to have heat shielding properties, either thelight emitting layer or the first resin layer, or both of them maycontain a heat wave absorbing agent. Alternatively, a heat waveshielding layer containing a heat wave absorbing agent may further belaminated in addition to the light emitting layer and the first resinlayer.

The heat wave absorbing agent is not particularly limited, as long as itshields infrared rays. Preferred is at least one selected from the groupconsisting of tin-doped indium oxide (ITO) particles, antimony-doped tinoxide (ATO) particles, aluminum-doped zinc oxide (AZO) particles,indium-doped zinc oxide (IZO) particles, tin-doped zinc oxide particles,silicon-doped zinc oxide particles, lanthanum hexaboride particles, andcerium hexaboride particles.

The interlayer film for laminated glass of the present invention mayfurther include a sound insulation layer in order to improve the soundinsulation properties. Either the light emitting layer or the firstresin layer may have sound insulation properties to function as a soundinsulation layer. Alternatively, a sound insulation layer may further belaminated in addition to the light emitting layer and the first resinlayer.

The sound insulation layer may be, for example, a layer containing theplasticizer in an amount of 50 to 80 parts by weight for 100 parts byweight of the polyvinyl acetal. The sound insulation layer preferablycontains a polyvinyl acetal, and more preferably contains polyvinylbutyral. As for the polyvinyl acetal in the sound insulation layer, thehydroxyl group content is preferably in the range of 20 to 28 mol %. Thepolyvinyl acetal in the sound insulation layer may be polyvinyl acetal Ahaving an acetyl group content of 8 to 30 mol %, polyvinyl acetal Bhaving an acetyl group content of more than 0 mol % and less than 5 mol% and a degree of acetalization of 70 to 85 mol %, or polyvinyl acetal Chaving an acetyl group content of 5 mol % or more and less than 8 mol %and a degree of acetalization of 65 to 80 mol %.

Preferably, in the interlayer film for laminated glass of the presentinvention, the light emitting layer (as a surface layer), the firstresin layer (as an intermediate layer), and the light emitting layer (asa surface layer) are laminated in the stated order, for example. In thecase where the light emitting layers constitute the surface layers ofthe interlayer film for laminated glass, the interlayer film forlaminated glass can produce a high contrast image, is less susceptibleto color changes, and allows for control of the adhesion. In the casewhere the first resin layer has sound insulation properties, theinterlayer film for laminated glass has improved sound insulationproperties.

In order to ensure that the interlayer film for laminated glass of thepresent invention has sound insulation properties, the amount(hereinafter, also referred to as amount X) of the plasticizer in thefirst resin layer relative to 100 parts by weight of the polyvinylacetal in the first resin layer is preferably larger than the amount(hereinafter, also referred to as amount Y) of the plasticizer in thelight emitting layer relative to 100 parts by weight of the polyvinylacetal in the light emitting layer. The amount X is preferably largerthan the amount Y by 5 parts by weight or more, more preferably by 10parts by weight or more, and still more preferably by 15 parts by weightor more. In order to ensure that the interlayer film for laminated glasshas much higher penetration resistance, the difference between theamount X and the amount Y is preferably 50 parts by weight or less, morepreferably 40 parts by weight or less, and still more preferably 35parts by weight or less. The difference between the amount X and theamount Y is determined by the following formula:

(Difference between amount X and amount Y)=(Amount X−Amount Y).

In the case where the following conditions are satisfied: the lightemitting layer and the first resin layer contain the polyvinyl acetaland the plasticizer; and the light emitting layer is disposed on orabove both one surface of the first resin layer and the other surface ofthe first resin layer opposite to the one surface, the hydroxyl groupcontent (hereinafter, also referred to as hydroxyl group content X) ofthe polyvinyl acetal in the first resin layer is preferably less thanthe hydroxyl group content (hereinafter, also referred to as hydroxylgroup content Y) of the polyvinyl acetal in the light emitting layer.When the hydroxyl group content X is less than the hydroxyl groupcontent Y, the plasticizer in the first resin layer is prevented frommigrating to the light emitting layer. As a result, the sound insulationproperties of the interlayer film for laminated glass can be improved.

The hydroxyl group content X is more preferably less than the hydroxylgroup content Y by 1 mol % or more, still more preferably by 3 mol % ormore, and particularly preferably by 5 mol % or more. In order tofacilitate formation of the interlayer film for laminated glass, thepreferable upper limit of the difference between the hydroxyl groupcontent X and the hydroxyl group content Y is 20 mol %, the morepreferable upper limit is 15 mol %, the still more preferable upperlimit is 12 mol %, and the particularly preferable upper limit is 10 mol%. The difference between the hydroxyl group content X and the hydroxylgroup content Y is determined by the following formula:

(Difference between hydroxyl group content X and hydroxyl group contentY)=(hydroxyl group content Y−hydroxyl group content X).

In order to prevent the plasticizer from migrating from the first resinlayer to the light emitting layer, and to prevent the light emittingmaterial having a terephthalic acid ester structure from migrating fromthe light emitting layer to the first resin layer, a layer forpreventing the plasticizer or the light emitting material having aterephthalic acid ester structure from migrating may be disposed betweenthe light emitting layer and the first resin layer. Examples of thelayer for preventing migration include a resin layer containing apolyalkylene terephthalate such as polyethylene terephthalate.

The preferable lower limit of the hydroxyl group content X is 10 mol %,the more preferable lower limit is 15 mol %, the still more preferablelower limit is 18 mol %, and the particularly preferable lower limit is20 mol %. The preferable upper limit of the hydroxyl group content X is32 mol %, the more preferable upper limit is 30 mol %, the still morepreferable upper limit is 28 mol %, and the particularly preferableupper limit is 25 mol %. When the hydroxyl group content X is the lowerlimit or more, the interlayer film for laminated glass has highpenetration resistance; when the content is the upper limit or less, thefirst resin layer can be easily formed. The preferable lower limit ofthe hydroxyl group content Y is 26 mol %, the more preferable lowerlimit is 28 mol %, the still more preferable lower limit is 30 mol %,the preferable upper limit is 40 mol %, the more preferable upper limitis 36 mol %, the still more preferable upper limit is 34 mol %, and theparticularly preferable upper limit is 32 mol %. When the hydroxyl groupcontent Y is the lower limit or more, the interlayer film for laminatedglass has high penetration resistance; when the content is the upperlimit or less, the light emitting layer can be easily formed.

The interlayer film for laminated glass of the present invention can beformed by any method without particular limitation, and examples includea method for forming an interlayer film for laminated glass whichinvolves using a plasticizer solution prepared by mixing theplasticizer, the light emitting material having a terephthalic acidester structure, and the potassium salt, and a resin compositioncontaining the polyvinyl acetal. Preferably, the obtained resincomposition is sufficiently mixed and then extruded with an extruderinto an interlayer film for laminated glass. The plasticizer solutionprepared by mixing the plasticizer, the light emitting material having aterephthalic acid ester structure, and the potassium salt, and the resincomposition containing the polyvinyl acetal may be coextruded with aresin composition containing the polyvinyl acetal and the plasticizer toform a multilayered interlayer film including the light emitting layer,the first resin layer, and the light emitting layer.

Because of the light emitting layer, the interlayer film for laminatedglass of the present invention emits light under radiation of light atspecific wavelengths. This feature allows for display of informationwith a high contrast.

Examples of devices for radiation of light at specific wavelengthsinclude a spot light source (LC-8 from Hamamatsu Photonics K.K.), axenon flush lamp (CW lamp from Heraeus), and a black light (Carry Handfrom Iuchi Seieido Co., Ltd.).

A laminated glass including the interlayer film for laminated glass ofthe present invention between a pair of glass plates is also one aspectof the present invention.

The glass plates may be common transparent glass plates. Examplesinclude plates of inorganic glasses such as float glass plate, polishedglass plate, figured glass plate, meshed glass plate, wired glass plate,colored glass plate, heat-absorbing glass plate, heat-reflecting glassplate, and green glass plate. An ultraviolet shielding glass plateincluding an ultraviolet shielding coat layer on a glass surface mayalso be used. However, this glass plate is preferably used on the sideopposite to the side to be exposed to radiation of light at specificwavelengths. Further examples of the glass plates include organicplastic plates made of polyethylene terephthalate, polycarbonate,polyacrylate, or the like.

The glass plates may include two or more types of glass plates. Forexample, the laminated glass may be a laminate including the interlayerfilm for laminated glass of the present invention between a transparentfloat glass plate and a colored glass plate such as a green glass plate.The glass plates may include two or more glass plates with a differentthickness.

Advantageous Effects of Invention

The present invention provides an interlayer film for laminated glasswhich produces a high contrast image under light radiation, is lesssusceptible to color changes, and allows for control of the adhesion.The present invention further provides a laminated glass including theinterlayer film for laminated glass.

DESCRIPTION OF EMBODIMENTS

The following examples are offered to demonstrate the present invention,but are not to be construed as limiting the present invention.

Example 1 (1) Resin Composition for Light Emitting Layer

A light-emissive plasticizer solution was prepared by mixing 0.2 partsby weight of diethyl-2,5-dihydroxy terephthalate(“diethyl-2,5-dihydroxyterephthalate” from Aldrich), which correspondsto the compound having a structure represented by the formula (1), asthe light emitting material having a terephthalic acid ester structure,and 0.056 parts by weight of potassium acetate as the potassium saltwith 40 parts by weight of triethyleneglycol di-2-ethylhexanoate (3GO).The entire amount of the plasticizer solution was combined with 100parts by weight of polyvinyl butyral (acetyl group content: 0.9 mol %,hydroxyl group content: 30.6 mol %, degree of butyralization: 68.5 mol%) obtained by acetalization of a polyvinyl alcohol (degree ofpolymerization: 1700) with n-butylaldehyde. The resulting mixture wassufficiently kneaded with mixing rolls. In this manner, a resincomposition for a light emitting layer was prepared.

(2) Formation of Interlayer Film for Laminated Glass

An interlayer film for laminated glass (30 cm (length)×15 cm (width))consisting of a light emitting layer was formed by extrusion of theresin composition for a light emitting layer from an extruder. Thethickness of the interlayer film for laminated glass was 800 μm.

(3) Production of Laminated Glass

The interlayer film for laminated glass was inserted between a pair of30 cm (length)×15 cm (width) clear glass plates (thickness: 2.5 mm) toprepare a laminate. Pressure bonding was carried out by vacuum pressingof the laminate with a vacuum laminator at 90° C. for 30 minutes. Afterpressure bonding, the laminate was further pressure bonded in anautoclave at 140° C. at 14 MPa for 20 minutes. In this manner, alaminated glass was obtained.

Examples 2 to 19 and Comparative Example 1

An interlayer film for laminated glass and a laminated glass wereobtained in the same manner as in Example 1, except that the compositionwas changed as shown in Tables 1 and 2.

Example 20 (1) Resin Composition for Surface Layer

A light-emissive plasticizer solution was prepared by mixing 0.6 partsby weight of diethyl-2,5-dihydroxy terephthalate(“diethyl-2,5-dihydroxyterephthalate” from Aldrich), which correspondsto the compound having a structure represented by the formula (1), asthe light emitting material having a terephthalic acid ester structure,and 0.056 parts by weight of potassium acetate as the potassium saltwith 40 parts by weight of triethyleneglycol di-2-ethylhexanoate (3GO).The entire amount of the plasticizer solution was combined with 100parts by weight of polyvinyl butyral (acetyl group content: 0.9 mol %,hydroxyl group content: 30.6 mol %, degree of butyralization: 68.5 mol%) obtained by acetalization of a polyvinyl alcohol (degree ofpolymerization: 1700) with n-butylaldehyde. The resulting mixture wassufficiently kneaded with mixing rolls. In this manner, a resincomposition for a surface layer was prepared.

(2) Resin Composition for Intermediate Layer

A resin composition for an intermediate layer was prepared bysufficiently kneading 60 parts by weight of triethyleneglycoldi-2-ethylhexanoate (3GO) with 100 parts by weight of polyvinyl butyral(acetyl group content: 13 mol %, hydroxyl group content: 22 mol %,degree of butyralization: 65 mol %) obtained by acetalization of apolyvinyl alcohol (degree of polymerization: 2300) with n-butylaldehydewith mixing rolls.

(3) Formation of Interlayer Film for Laminated Glass

The resin composition for a surface layer and the resin composition foran intermediate layer were extruded from a coextruder to form aninterlayer film for laminated glass (30 cm (length)×15 cm (width))including three layers: a surface layer (thickness: 350 μm)/anintermediate layer (thickness: 100 μm)/a surface layer (thickness: 350μm). The thickness of the interlayer film for laminated glass was 800μm.

(4) Production of Laminated Glass

The interlayer film for laminated glass was inserted between a pair of30 cm (length)×15 cm (width) clear glass plates (thickness: 2.5 mm) toprepare a laminate. Pressure bonding was carried out by vacuum pressingof the laminate with a vacuum laminator at 90° C. for 30 minutes. Afterpressure bonding, the laminate was further pressure bonded in anautoclave at 140° C. at 14 MPa for 20 minutes. In this manner, alaminated glass was obtained.

Examples 21 to 42 and Comparative Examples 2, 3

An interlayer film for laminated glass and a laminated glass wereobtained in the same manner as in Example 20, except that thecompositions of the surface layers and the intermediate layer werechanged as shown in Tables 3 to 7.

(Evaluation)

The laminated glasses obtained in the examples and comparative exampleswere evaluated as follows. Tables 1 to 7 show the results.

(1) Evaluation of Light Emission

An entire surface of each of the laminated glasses was irradiated withlight from a high power xenon light source (“REX-250” from Asahi SpectraCo., Ltd., emission at 405 nm) in a dark room. The laminated glasseswere visually observed, and those emitting light from a center portionthereof were given a rating of “O”, and those which did not emit lightwere given a rating of “x”. The entire surface of each laminated glasswas further irradiated in a dark room with light from the high powerxenon light source (“REX-250” from Asahi Spectra Co., Ltd., emission at405 nm) that was spaced 10 cm from the laminated glass surface in theperpendicular direction, and measured for luminance with a luminancemeter (“SR-3AR” from TOPCON TECHNOHOUSE CORPORATION) that was positionedon the side being irradiated with light at an angle of 45 degrees withrespect to the laminated glass surface being irradiated with light, andspaced a minimum distance of 35 cm from the laminated glass surface.

(2) Evaluation of Color Change

The laminated glasses (5 cm (length)×5 cm (width)) were measured for theyellow index value (YI value) with a spectrophotometer (U-4100 fromHitachi High-Technologies Corporation) in accordance with JIS Z 8722.Their yellow index values (YI values) were evaluated as follows: whenthe YI value is 0 or more and 20 or less, a rating of “O” was given; andwhen the YI value is more than 20, a rating of “x” was given.

(3) Evaluation of Adhesion (Measurement of Pummel Value of InterlayerFilm for Laminated Glass)

The laminated glasses obtained in the examples and comparative exampleswere left standing at −18° C.±0.6° C. for 16 hours, and a center portion(150 mm (length)×150 mm (width)) of each laminated glass was shatteredwith a hammer having a 0.45 kg head into glass pieces with a size of 6mm or smaller. Areas of the films from which glass pieces fell off weremeasured for exposure degree, and a pummel value was assigned based onthe classifications indicated in Table 8. A pummel value of 2 to 9 wasevaluated as “O”, and a pummel value of 1 or less or of 10 was evaluatedas “x”. The pummel values are also shown.

TABLE 1 Example 1 Example 2 Example 3 Example 4 Example 5 Light emittingPolyvinyl butyral Parts by weight 100 100 100 100 100 layer Degree ofpolymerization 1700 1700 1700 1700 1700 Hydroxyl group content 30.6 30.630.6 30.6 30.6 (mol %) Degree of butyralization 68.5 68.5 68.5 68.5 68.5(mol %) Acetyl group content 0.9 0.9 0.9 0.9 0.9 (mol %) Plasticizer(3GO) Parts by weight 40 40 40 40 40 Light emittingDiethyl-2,5-dihydroxy Parts by weight 0.2 0.2 0.2 0.2 0.2 materialhaving terephthalate terephthalic acid Dimethyl-2,5-dihydroxy Parts byweight 0 0 0 0 0 ester structure terephthalate Diethyl-2,5-diamino Partsby weight 0 0 0 0 0 terephthalate Potassium salt Potassium acetate Partsby weight 0.056 0.084 0.028 0.042 0.056 Potassium Parts by weight 0 00.052 0.078 0 2-ethylhexanoate Potassium formate Parts by weight 0 0 0 00 Potassium propionate Parts by weight 0 0 0 0 0 Magnesium saltMagnesium acetate Parts by weight 0 0 0 0 0.049 tetrahydrate Potassiumconcentration ppm 160 240 160 240 160 Magnesium concentration ppm 0 0 00 40 Thickness of light emitting layer μm 800 800 800 800 800 EvalutionLight emission Evaluation ◯ ◯ ◯ ◯ ◯ Luminance (cd/m²) 750 753 751 755745 Color change Evaluation ◯ ◯ ◯ ◯ ◯ Initial YI 7 7 7 7 10 AdhesionEvaluation ◯ ◯ ◯ ◯ ◯ Pummel value 4 3 5 4 4 Example 6 Example 7 Example8 Example 9 Example 10 Light emitting Polyvinyl butyral Parts by weight100 100 100 100 100 layer Degree of polymerization 1700 1700 1700 17001700 Hydroxyl group content 30.6 30.6 30.6 30.6 30.7 (mol %) Degree ofbutyralization 68.5 68.5 68.5 68.5 68.5 (mol %) Acetyl group content 0.90.9 0.9 0.9 0.8 (mol %) Plasticizer (3GO) Parts by weight 40 40 40 40 40Light emitting Diethyl-2,5-dihydroxy Parts by weight 0.2 0.2 0.2 0.2 0.2material having terephthalate terephthalic acid Dimethyl-2,5-dihydroxyParts by weight 0 0 0 0 0 ester structure terephthalateDiethyl-2,5-diamino Parts by weight 0 0 0 0 0 terephthalate Potassiumsalt Potassium acetate Parts by weight 0.056 0.056 0.018 0.11 0.056Potassium Parts by weight 0 0 0 0 0 2-ethylhexanoate Potassium formateParts by weight 0 0 0 0 0 Potassium propionate Parts by weight 0 0 0 0 0Magnesium salt Magnesium acetate Parts by weight 0.074 0.025 0 0 0tetrahydrate Potassium concentration ppm 160 160 50 300 160 Magnesiumconcentration ppm 60 20 0 0 0 Thickness of light emitting layer μm 800800 800 800 800 Evalution Light emission Evaluation ◯ ◯ ◯ ◯ ◯ Luminance(cd/m²) 735 748 750 758 751 Color change Evaluation ◯ ◯ ◯ ◯ ◯ Initial YI14 8.5 7 7 7 Adhesion Evaluation ◯ ◯ ◯ ◯ ◯ Pummel value 3 4 7 2 4

TABLE 2 Example 11 Example 12 Example 13 Example 14 Example 15 LightPolyvinyl butyral Parts by weight 100 100 100 100 100 emitting Degree of1700 1700 1700 1700 1700 layer polymerization Hydroxyl group 29.9 30.630.6 30.6 30.6 content (mol %) Degree of 68.5 68.5 68.5 68.5 68.5butyralization (mol %) Acetyl group 1.6 0.9 0.9 0.9 0.9 content (mol %)Plasticizer (3GO) Parts by weight 40 40 40 40 40 Light emittingDiethyl-2,5-dihydroxy Parts by weight 0.2 0 0 0.2 0.2 material havingterephthalate terephthalic acid Dimethyl-2,5-dihydroxy Parts by weight 00.2 0.8 0 0 ester structure terephthalate Diethyl-2,5-diamino Parts byweight 0 0 0 0 0 terephthalate Potassium salt Potassium acetate Parts byweight 0.056 0.056 0.056 0 0 Potassium Parts by weight 0 0 0 0 02-ethylhexanoate Potassium formate Parts by weight 0 0 0 0.047 0Potassium propionate Parts by weight 0 0 0 0 0.063 Magnesium saltMagnesium acetate Parts by weight 0 0 0 0 0 tetrahydrate Potassiumconcentration ppm 160 160 160 160 160 Magnesium concentration ppm 0 0 00 0 Thickness of light emitting layer μm 800 800 800 800 800 EvalutionLight emission Evaluation ◯ ◯ ◯ ◯ ◯ Luminance 752 756 950 754 759(cd/m²) Color change Evaluation ◯ ◯ ◯ ◯ ◯ Initial YI 7 7 7 7 7 AdhesionEvaluation ◯ ◯ ◯ ◯ ◯ Pummel value 4 4 4 4 4 Comparative Example 16Example 17 Example 18 Example 19 Example 1 Light Polyvinyl butyral Partsby weight 100 100 100 100 100 emitting Degree of 1700 1700 1700 17001700 layer polymerization Hydroxyl group 30.6 30.6 30.6 30.6 30.6content (mol %) Degree of 68.5 68.5 68.5 68.5 68.5 butyralization (mol%) Acetyl group 0.9 0.9 0.9 0.9 0.9 content (mol %) Plasticizer (3GO)Parts by weight 40 40 40 40 40 Light emitting Diethyl-2,5-dihydroxyParts by weight 0.5 0.8 0 0 0.2 material having terephthalateterephthalic acid Dimethyl-2,5-dihydroxy Parts by weight 0 0 0 0 0 esterstructure terephthalate Diethyl-2,5-diamino Parts by weight 0 0 0.2 0.80 terephthalate Potassium salt Potassium acetate Parts by weight 0.0560.056 0.056 0.056 0 Potassium Parts by weight 0 0 0 0 0 2-ethylhexanoatePotassium formate Parts by weight 0 0 0 0 0 Potassium propionate Partsby weight 0 0 0 0 0 Magnesium salt Magnesium acetate Parts by weight 0 00 0 0.11 tetrahydrate Potassium concentration ppm 160 160 160 160 0Magnesium concentration ppm 0 0 0 0 90 Thickness of light emitting layerμm 800 800 800 800 800 Evalution Light emission Evaluation ◯ ◯ ◯ ◯ ◯Luminance 920 1000 732 935 725 (cd/m²) Color change Evaluation ◯ ◯ ◯ ◯ XInitial YI 7 7 7 7 21 Adhesion Evaluation ◯ ◯ ◯ ◯ ◯ Pummel value 4 4 4 44

TABLE 3 Example Example Example Example 20 21 22 23 Example 24Intermediate Polyvinyl butyral Parts by weight 100 100 100 100 100 layerDegree of polymerization 2300 2300 2300 2300 2300 Hydroxyl group content22 22 22 22 22 (mol %) Degree of butyralization 65 65 65 65 65 (mol %)Acetyl group content 13 13 13 13 13 (mol %) Plasticizer (3GO) Parts byweight 60 60 60 60 60 Potassium acetate Parts by weight 0 0 0 0 0Potassium 2-ethylhexanoate Parts by weight 0 0 0 0 0 Potassium formateParts by weight 0 0 0 0 0 Potassium propionate Parts by weight 0 0 0 0 0Magnesium acetate tetrahydrate Parts by weight 0 0 0 0 0 Light emittingDiethyl-2,5-dihydroxy Parts by weight 0 0 0 0 0 material havingterephthalate terephthalic acid Dimethyl-2,5-dihydroxy Parts by weight 00 0 0 0 ester structure terephthalate Potassium concentration ppm 0 0 00 0 Magnesium concentration ppm 0 0 0 0 0 Thickness of intermediatelayer μm 100 100 100 100 100 Surface layer Polyvinyl butyral Parts byweight 100 100 100 100 100 Degree of polymerization 1700 1700 1700 17001700 Hydroxyl group content 30.6 30.6 30.6 30.6 30.6 (mol %) Degree ofbutyralization 68.5 68.5 68.5 68.5 68.5 (mol %) Acetyl group content 0.90.9 0.9 0.9 0.9 (mol %) Plasticizer (3GO) Parts by weight 40 40 40 40 40Adhesion control Potassium acetate Parts by weight 0.056 0 0 0.056 0.084agent Potassium 2-ethylhexanoate Parts by weight 0 0 0 0 0 Potassiumformate Parts by weight 0 0.047 0 0 0 Potassium propionate Parts byweight 0 0 0.063 0 0 Magnesium acetate Parts by weight 0 0 0 0.049 0tetrahydrate Light emitting Diethyl-2,5-dihydroxy Parts by weight 0.60.6 0.6 0.6 0.6 material having terephthalate terephthalic acidDimethyl-2,5-dihydroxy Parts by weight 0 0 0 0 0 ester structureterephthalate Potassium concentration ppm 160 160 160 160 240 Magnesiumconcentration ppm 0 0 0 40 0 Thickness of surface layer μm 350 350 350350 350 Evalution Evaluation of light emission Luminance (cd/m²) 925 923935 920 940 Evaluation of color change Initial YI 7 7 7 10 7 Evaluationof adhesion Pummel value 4 4 4 4 3

TABLE 4 Example Example Example Example 25 26 27 28 Example 29Intermediate Polyvinyl butyral Parts by weight 100 100 100 100 100 layerDegree of polymerization 2300 2300 2300 2300 2300 Hydroxyl group content22 22 22 22 22 (mol %) Degree of butyralization 65 65 65 65 65 (mol %)Acetyl group content 13 13 13 13 13 (mol %) Plasticizer (3GO) Parts byweight 60 60 60 60 60 Potassium acetate Parts by weight 0 0 0 0 0.028Potassium 2-ethylhexanoate Parts by weight 0 0 0 0 0 Potassium formateParts by weight 0 0 0 0 0 Potassium propionate Parts by weight 0 0 0 0 0Magnesium acetate tetrahydrate Parts by weight 0 0 0 0 0 Light emittingDiethyl-2,5-dihydroxy Parts by weight 0 0 0.5 0.5 0.5 material havingterephthalate terephthalic acid Dimethyl-2,5-dihydroxy Parts by weight 00 0 0 0 ester structure terephthalate Potassium concentration ppm 0 0 00 80 Magnesium concentration ppm 0 0 0 0 0 Thickness of intermediatelayer μm 100 100 100 100 100 Surface layer Polyvinyl butyral Parts byweight 100 100 100 100 100 Degree of polymerization 1700 1700 1700 17001700 Hydroxyl group content 30.6 30.6 30.6 30.6 30.6 (mol %) Degree ofbutyralization 68.5 68.5 68.5 68.5 68.5 (mol %) Acetyl group content 0.90.9 0.9 0.9 0.9 (mol %) Plasticizer (3GO) Parts by weight 40 40 40 40 40Adhesion control Potassium acetate Parts by weight 0.084 0.056 0.0560.056 0.056 agent Potassium 2-ethylhexanoate Parts by weight 0 0 0 0 0Potassium formate Parts by weight 0 0 0 0 0 Potassium propionate Partsby weight 0 0 0 0 0 Magnesium acetate Parts by weight 0 0 0 0.049 0tetrahydrate Light emitting Diethyl-2,5-dihydroxy Parts by weight 0.8 00.5 0.5 0.5 material having terephthalate terephthalic acidDimethyl-2,5-dihydroxy Parts by weight 0 0.6 0 0 0 ester structureterephthalate Potassium concentration ppm 240 160 160 160 160 Magnesiumconcentration ppm 0 0 0 40 0 Thickness of surface layer μm 350 350 350350 350 Evalution Evaluation of light emission Luminance (cd/m²) 970 920920 923 921 Evaluation of color change Initial YI 8 7 7 10 7 Evaluationof adhesion Pummel value 3 4 4 4 4

TABLE 5 Example Example Example Example 30 31 32 33 Example 34Intermediate Polyvinyl butyral Parts by weight 100 100 100 100 100 layerDegree of polymerization 2300 2300 2300 2300 2300 Hydroxyl group content22 16 24 22 22 (mol %) Degree of butyralization 65 71 60 65 65 (mol %)Acetyl group content 13 13 16 13 13 (mol %) Plasticizer (3GO) Parts byweight 60 60 60 60 60 Potassium acetate Parts by weight 0 0 0 0 0Potassium 2-ethylhexanoate Parts by weight 0 0 0 0 0 Potassium formateParts by weight 0 0 0 0 0 Potassium propionate Parts by weight 0 0 0 0 0Magnesium acetate tetrahydrate Parts by weight 0.049 0 0 0 0 Lightemitting Diethyl-2,5-dihydroxy Parts by weight 0.5 0 0 0 0 materialhaving terephthalate terephthalic acid Dimethyl-2,5-dihydroxy Parts byweight 0 0 0 0 0 ester structure terephthalate Potassium concentrationppm 0 0 0 0 0 Magnesium concentration ppm 40 0 0 0 0 Thickness ofintermediate layer μm 100 100 100 100 100 Surface layer Polyvinylbutyral Parts by weight 100 100 100 100 100 Degree of polymerization1700 1700 1700 1700 1700 Hydroxyl group content 30.6 30.6 30.6 30.7 30.1(mol %) Degree of butyralization 68.5 68.5 68.5 68.5 68.3 (mol %) Acetylgroup content 0.9 0.9 0.9 0.8 1.6 (mol %) Plasticizer (3GO) Parts byweight 40 40 40 40 40 Adhesion control Potassium acetate Parts by weight0.056 0.056 0.056 0.056 0.056 agent Potassium 2-ethylhexanoate Parts byweight 0 0 0 0 0 Potassium formate Parts by weight 0 0 0 0 0 Potassiumpropionate Parts by weight 0 0 0 0 0 Magnesium acetate Parts by weight 00 0.049 0 0.049 tetrahydrate Light emitting Diethyl-2,5-dihydroxy Partsby weight 0.5 0.6 0.6 0.6 0.6 material having terephthalate terephthalicacid Dimethyl-2,5-dihydroxy Parts by weight 0 0 0 0 0 ester structureterephthalate Potassium concentration ppm 160 160 160 160 160 Magnesiumconcentration ppm 0 0 40 0 40 Thickness of surface layer μm 350 350 350350 350 Evalution Evaluation of light emission Luminance (cd/m²) 918 927921 920 918 Evaluation of color change Initial YI 10 7 10 7 10Evaluation of adhesion Pummel value 4 4 4 4 4

TABLE 6 Example Example Example Example 35 36 37 38 Example 39Intermediate Polyvinyl butyral Parts by weight 100 100 100 100 100 layerDegree of 2300 2300 2300 1700 3000 polymerization Hydroxyl group 22 2222 30.6 22 content (mol %) Degree of 65 65 65 68.5 65 butyralization(mol %) Acetyl group 13 13 13 0.9 13 content (mol %) Plasticizer (3GO)Parts by weight 70 50 45 40 60 Potassium acetate Parts by weight 0 0 0 00 Potassium Parts by weight 0 0 0 0 0 2-ethylhexanoate Potassium formateParts by weight 0 0 0 0 0 Potassium propionate Parts by weight 0 0 0 0 0Magnesium acetate Parts by weight 0 0 0 0 0 tetrahydrate Light emittingDiethyl-2,5-dihydroxy Parts by weight 0 0 0 0 0 material havingterephthalate terephthalic acid Dimethyl-2,5-dihydroxy Parts by weight 00 0 0 0 ester structure terephthalate Potassium concentration ppm 0 0 00 0 Magnesium concentration ppm 0 0 0 0 0 Thickness of intermediatelayer μm 100 100 100 100 100 Surface Polyvinyl butyral Parts by weight100 100 100 100 100 layer Degree of 1700 1700 1700 1700 1700polymerization Hydroxyl group 30.6 30.6 30.6 30.6 30.6 content (mol %)Degree of 68.5 68.5 68.5 68.5 68.5 butyralization (mol %) Acetyl group0.9 0.9 0.9 0.9 0.9 content (mol %) Plasticizer (3GO) Parts by weight 4040 40 40 40 Adhesion control Potassium acetate Parts by weight 0.0560.056 0.056 0.056 0 agent Potassium 2-ethylhexanoate Parts by weight 0 00 0 0 Potassium formate Parts by weight 0 0 0 0 0.047 Potassiumpropionate Parts by weight 0 0 0 0 0 Magnesium acetate tetrahydrateParts by weight 0 0 0 0 0 Light emitting Diethyl-2,5-dihydroxy Parts byweight 0.6 0.6 0.6 0.6 0.6 material having terephthalate terephthalicacid Dimethyl-2,5-dihydroxy Parts by weight 0 0 0 0 0 ester structureterephthalate Potassium concentration ppm 160 160 160 160 160 Magnesiumconcentration ppm 0 0 0 0 0 Thickness of surface layer μm 350 350 350350 350 Evalution Evaluation of light emission Luminance (cd/m²) 928 926929 922 928 Evaluation of color change Initial YI 7 7 7 7 7 Evaluationof adhesion Pummel value 4 4 4 4 4

TABLE 7 Comparative Comparative Example 40 Example 41 Example 42 Example2 Example 3 Inter- Polyvinyl butyral Parts by weight 100 100 100 100 100mediate Degree of 3000 3000 3000 2300 2300 layer polymerization Hydroxylgroup 22 22 22 22 22 content (mol %) Degree of 65 65 65 65 65butyralization (mol %) Acetyl group 13 13 13 13 13 content (mol %)Plasticizer (3GO) Parts by weight 60 60 60 60 60 Potassium acetate Partsby weight 0 0 0 0 0 Potassium 2-ethylhexanoate Parts by weight 0 0 0 0 0Potassium formate Parts by weight 0 0 0 0 0 Potassium propionate Partsby weight 0 0 0 0 0 Magnesium acetate tetrahydrate Parts by weight 0 0 00 0.11 Light emitting Diethyl-2,5-dihydroxy Parts by weight 0 0 0 0 0.5material having terephthalate terephthalic acid Dimethyl-2,5-dihydroxyParts by weight 0 0 0 0 0 ester structure terephthalate Potassiumconcentration ppm 0 0 0 0 0 Magnesium concentration ppm 0 0 0 0 90Thickness of intermediate layer μm 100 100 100 100 100 Surface Polyvinylbutyral Parts by weight 100 100 100 100 100 layer Degree of 1700 17001700 1700 1700 polymerization Hydroxyl group 30.6 30.6 30.6 30.6 30.6content (mol %) Degree of 68.5 68.5 68.5 68.5 68.5 butyralization (mol%) Acetyl group 0.9 0.9 0.9 0.9 0.9 content (mol %) Plasticizer (3GO)Parts by weight 40 40 40 40 40 Adhesion control Potassium acetate Partsby weight 0 0.056 0.056 0 0 agent Potassium 2- Parts by weight 0 0 0 0 0ethylhexanoate Potassium formate Parts by weight 0 0 0 0 0 Potassiumpropionate Parts by weight 0.063 0 0 0 0 Magnesium acetate Parts byweight 0 0 0 0.11 0.11 tetrahydrate Light emitting Diethyl-2,5-dihydroxyParts by weight 0.6 0 0.6 0.6 0.5 material having terephthalateterephthalic acid Dimethyl-2,5-dihydroxy Parts by weight 0 0.6 0 0 0ester structure terephthalate Potassium concentration ppm 160 160 160 00 Magnesium concentration ppm 0 0 0 90 90 Thickness of surface layer μm350 350 350 350 350 Evalution Evaluation of light emission Luminance 929921 920 910 912 (cd/m²) Evaluation of color change Initial YI 7 7 7 3035 Evaluation of adhesion Pummel value 4 4 4 4 4

TABLE 8 Exposure degree of interlayer Pummel film (area %) value 90 <Exposure degree ≦ 100 0 85 < Exposure degree ≦ 90 1 60 < Exposure degree≦ 85 2 40 < Exposure degree ≦ 60 3 20 < Exposure degree ≦ 40 4 10 <Exposure degree ≦ 20 5 5 < Exposure degree ≦ 10 6 2 < Exposure degree ≦5 7 Exposure degree ≦ 2 8

INDUSTRIAL APPLICABILITY

The present invention provides an interlayer film for laminated glasswhich produces a high contrast image under light radiation, is lesssusceptible to color changes, and allows for control of the adhesion.The present invention further provides a laminated glass including theinterlayer film for laminated glass.

1. An interlayer film for laminated glass comprising a light emittinglayer containing a polyvinyl acetal, a light emitting material having aterephthalic acid ester structure, and a potassium salt.
 2. Theinterlayer film for laminated glass according to claim 1, wherein thelight emitting material having a terephthalic acid ester structure is acompound having a structure represented by the following formula (1) ora compound having a structure represented by the following formula (2):

in the formula (1), R¹ being an organic group, and x being 1, 2, 3 or 4,and in the formula (2), R² being an organic group, R³ and R⁴individually being a hydrogen atom or an organic group, and y being 1,2, 3 or
 4. 3. The interlayer film for laminated glass according to claim1, wherein the light emitting layer comprises 0.001 to 5 parts by weightof the light emitting material having a terephthalic acid esterstructure for 100 parts by weight of the polyvinyl acetal.
 4. Theinterlayer film for laminated glass according 1, wherein a potassiumelement content of the light emitting layer is 250 ppm or less.
 5. Theinterlayer film for laminated glass according to claim 1, wherein thepotassium element content of the light emitting layer is 120 ppm ormore.
 6. The interlayer film for laminated glass according to claim 1,wherein a magnesium element content of the light emitting layer is 80ppm or less.
 7. The interlayer film for laminated glass according toclaim 1, wherein the light emitting layer contains magnesium element,and has a magnesium element content of 80 ppm or less.
 8. The interlayerfilm for laminated glass according to claim 1, wherein the potassiumsalt is a C1 to C16 carboxylic acid potassium salt.
 9. The interlayerfilm for laminated glass according to claim 1, wherein the potassiumsalt is potassium acetate, potassium propionate, potassium2-ethylbutanoate, or potassium 2-ethylhexanoate.
 10. A laminated glasscomprising a laminate including the interlayer film for laminated glassaccording to claim 1, between a pair of glass plates.